Manufacture of hydroxylamine sulfonates



Mlyr 4, 1954 R, N. G. zEEGERs 2,677,599

MANUFACTURE OF HYDROXYLAMINE SULFONATES Filed Feb. 16, 1951 5Sheets-Sheet l INVEVTR Rudolph N. G. Zeeyws ATTURNEYS F m." En

May 4, 1954 R 'N G ZEEGERS 2,677,599

' MANUFACTURE OF HYDROXYLAMINE SULFONATES Filed Feb. 16, 1951 3Sheets-Sheet 2 INVENTOR ATTORNEYS May 4, 1954 R. N. G. zEEGERs 2,677,599

MANUFACTURE oF HYDROXYLAMINE suLFoNATEs Filed Feb. 1e, 1951 ssheets-sheet s U52 INVENraR Ruda/Inh MG. Zeegers ATTORNEYS Patented May4, 1954 UNITED STATES PATENT GFFICE MANUFACTURE F HYDROXYLAMIN ESULFONATES Rudolph N. G. Zeegers, Beek, Netherlands, as-

signor to De Directie van de Staatsmijnen in Limburg, Heerlen,Netherlands Application February 16, 1951, Serial No. 211,255

Claims priority, application Netherlands February 22, 1950 Thisinvention relates to the manufacture of hydroxylamine sulfonates by thereaction of a nitrite and a bisulte in aqueous solution with sulfurdioxide.

Field of invention In the methods hitherto employed for manufacturinghydroxylamine sulfonates, using the above reaction, sodium salts havebeen commonly employed as the initial material and sodium hydroxide orsodium carbonate has been used instead of sodium bisulte, since sodiumbisulte is formed from said compounds by the action of sulfur dioxide.

If at a temperature of about 0 C., a sulfur dioxide-containing gas ispassed into an aqueous solution of sodium nitrite and sodium sulte, thesodium salt of hydroxylamine disulfonic acid is formed, and by observingcertain reaction conditions, a satisfactory yield can be obtained. Theconditions under which this very exothermic reaction proceeds rapidlyhave been the subject of many investigations which have resulted inembodiments of the reaction more adapted to manufacturing conditions.

Progress has been made in this field by employing a film reactor of thetype described in U. S. Patent No. 2,458,404. According to said patent,the sodium salt of hydroxylamine disulfonic acid is obtained by causingan aqueous solution of sodium nitrite and sodium bisulte to fiow down inthe form of a thin film over the inner surface of a vertical cylindricalfilm reactor, countercurrently to a stream of sulfur dioxide passing upthrough said reactor. As a result of the brief contact period in thefilm reactor, side reactions are avoided so that even temperatureshigher than C. are admissible.

Experience has shown that in methods above referred to diiculties areexperienced if ammonium compounds are employed instead of the nitriteand bisulte of an alkali metal. In this case, vapors are formed whichare entrained by the residual gas giving rise to high losses of ammoniawhich are not only disadvantageous from an economical viewpoint, butalso because they interfere with maintaining the proper ratio betweenthe reactants and undesirable variations are caused in the acidity ofthe reaction mixture. These difficulties become serious when gases witha low sulfur dioxide content, such as roasting gases, are employed,because then large amounts of gas have to be contacted with the reactionliquor and much residual gas is left to be carried off.

There is described in my application Serial No. 211,615, filed February19, 1951, and now abandoned, a process for producing a reaction liquorsuitable for the production of hydroxylamine sulfonates which includesthe steps of reacting an aqueous solution of ammonium nitrite andammonium bisuliite, or equivalent compound, with sulfur dioxide at a pHof between 5 and '7 thereby precipitating ammonium nitrilo-sulfonatefrom the reaction liquor, separating the precipitate from the liquor andcollecting the latter for further reaction with sulfur dioxide for thepurpose of forming hydroxylamine sulfonates. In the process of theabove-mentioned application, sulfur dioxide is passed in countercurrentrelationship with the ammonium compounds for the purpose of effectingthe desired reaction.

Objects A principal object of this invention is the provision of a newprocess for the manufacture of hydroxylamine sulfonates from ammoniumnitrite and sulfur dioxide-containing gases. Further objects include:

(l) The provision of such a process in which gases, for example,roasting gases, containing only small percentages of sulfur dioxide, canbe employed without giving rise to high losses of ammonia from thereaction liquors.

(2) The provision of new improvements in this general type of reactionwhich make possible the satisfactory control of proportions betweenessential reactants and maintenance of desired liquor acidities, so asto produce satisfactory product yields.

Still'further objects and the entire scope of applicability of thepresent invention will become apparent from the detailed descriptiongiven hereinafter; it should be understood, however, that the detaileddescription and specific examples, vvhile indicating preferredembodiments of the invention, are given by way of illustration only,since various changes and modifications Within the spirit and scope ofthe invention will become apparent to those skilled in the art from thisdetailed description.

General description formed as a une dispersion inthe sulfurdioxidecontaining gas stream and the resultingnvrnassis then caused toflow together :and 'concurrently in contact with a surface of large areaand low temperature, the vapors produced from the'am.- monium compoundcontaining solution do not give rise, as has,beenexperieneedpreviously,to losses of ammonia. At thesame time, this new typ f opration locatiesft DO'SSb12-lO'maintan a proper ratio between the various reactants andalso toobtain a controlled 'degrefeof acidity, so

lthat a satisfactory yield of yproduct results.

biscussioh or 'details--ovatus with considerable yaiiation in reactioncondionned to the employment of p llre sulfur, di- A oaideand gases witha high content of sulfur dioxide, but gases poor in sulfur dioxide aresuitable for the purpose. In particular, the roasting gases obtained bythe oxidation, of sulfur-containing ores, which gases usually containless than 10%, e. g. 2 to 8%, byyolume of sulfur dioxide, maybe employedwithout-,there being any danger that the vapors containing ammoniumcompounds formed during the reaction will be entrained bythe residualgas Various proportions between the diiTerentreaetants in the processcan be employed, although better and more desirable yields of productare obtained ifvcertain limitations on the proportions are observed.Preferably, the ammonium nitrite and the ammonium bisulte or equivalentammonium compounds which, upon reaction with sulfur dioxide in anaqueous medium, will Aform ammonium bisulte, e. g. ammonium hydroxide,or ammonium sulte should be present in the reaction mixture in aboutequal molecular proportions or with a slight v excess of the ammoniumbisulte or equivalent materials.

In the process; the preferred reaction temperaafter a nal liquor isobtained which largely consists of a solution of hydroxylaminedisulfonate. By means of hydrolysis, thi s can betconverted intohydroxylamine f monosulfonate rand, if desired, into hydroxylaminesulfate. The process according to the present inven- 4"tion can be morefully understood by reference togth'e accompanying diagrammaticdrawings, in which: Figure 1 isavertical section through one form oftheapparatus which may be used to carry out the, process oftheinvention;

Figure 2 is 'a vertical section through another 'form Vof apparatus;'and Figure 3 is a further form of apparatus with fsysterns `of coolingpipes shown in broken vertical section at the top and bottom of the gureand in 'exterior elevation in the middle broken portion of the figure.Referringto Figure 1, a vertical reaction ves- Sel lisproydeclwith aninlet epevr an. acueous solution o f ammonia and .ammonium nitritewhich, by means of a distributing ring 3, i s d i s tributed throughouta stream of sulfur dioxide containing gas which is introduced throughthe sasinlet 4 Subsequently', thejreactifon 1iq'uofr is passed, inconfiow with thejgas througha vtubular system consisting O f a numberofvertical coolingp'ipes 5, said pipes being cooled byaJ cooling liquorwhich 'is Yintroduced at ifandilows roundthe pipes. 5 towards thedischarge -pipe i. The cooling pipes 5 are packed with filling materialin order 'to 'D lomote the contact,between the reaction liquor,

: flowing down throughthe pipesand the gas.

The residual 'gas Ais,carried ofi through the gas `outlet 8, lthe`hydro'xylamineY sulfohate solution leaving the reactionvessel throughthe pipe s. Ihe discharge 'pipe lSlis provided with a goose I lcle |0so, Ithat there'sidualgas cannot pass through this o utlet f ortheliquor.

Referring to Figure 2, a helical reaction pipe lI2 is contained in 'a 4cylindrical vessel II. 'lj'he solution of ammonium nitrite and ammoniumhydroxide supplied through the pipe I3 is sprayed into the. pipe. l2throughthe `'nozzle I5, together with astream of roasting gas suppliedthrough thepipfe I 4. Subsequently, the reaction liquor I lows, inconlow withthe roasting gas, over the walls of the pipe I2, said wallsbeing Cooled by a cooling liquor which enters the vessel I! through theinlet IS and leaves vthrough the outlet ,II, Inan ,analogous manner, ashas been illustrated in Figure 1, the resulting solution ofhydroxylamine sulfonate is carried off through thepipe I8, Whereas theresidual gas leaves the separating vessel I9 through. the gas outlet 26.

Referring to Figure 3, an aqueous solution of the initiala'mmoniumcompounds isy continuously introduced into a cylindrical reaction.vessel 2l through the pipe 22 and the distributor 23, a sulfurdioxidecontaining gas being supplied through the gasinlet 24.Subsequently, thereaction liquor flows in conow with .the gasover theouter walls of the cooling pipes 25 whieh have been combined intosystems through which a cooling mediumis passed, said medium beingsupplied through the inlet pipes 26 and discharged through the pipes 2lin each system. The hydroxylamne sulfonate solutionobtained separatedromthegas in the separator 2E and carried ofl through thepipe 29, in, ananalogous manner, as has' been, illustrated 4in Figurel, whereas the gasleaves the apparatus through the gas outlet 30.

Example In order to provide for a fuller understanding of the proceduresas provided by this invention, there is given below an example of actualoperation in accordance with the invention for the production of anhydroxylamine sulfonate.

In an apparatus, as illustrated in Figure 1, an aqueous solution,containing 150 g. of ammonium nitrite and 84 g. of ammonium hydroxideper litre, is continuously run into the reaction vessel l through theinlet pipe 2 and sprayed therein with the help of the distributing ring3. Roasting gas, containing about 6% by volume of sulfur dioxide, iscontinuously supplied through the gas inlet s. The rate of delivery ofthe roasting gas is so adjusted at about 2000 liters per liter of theaqueous solution, that the reaction liquor, on leaving the system oftubes 5, has a pI-I value of about 3.5.

With the help of air, the reaction liquor leaving the reaction vessel isfreed from the sulfur dioxide still present therein. A nal liquor isobtained which contains hydroxylamine disulphonate with a concentrationof 69 to 72 g. per liter (calculated as NHzOH) which corresponds with ayield of over 90% based on the ammonium nitrite.

Conclusions New improvements in the generally known reaction for theformation of hydroxylamine sulfonates by reaction of nitries andbisultes with sulfur dioxide have been discussed. Through the use ofthese new improvements, it is possible to produce the hydroxylamines inhigh yield and with such economy of reaction materials that it ispossible to employ ammonium nitrite and ammonium bisuliite or similarsubstances in the reaction on a commercial basis. At the same time,specic embodiments of usable apparatus have been described by Which theimprovements can be carried out in a commercially feasible methodwithout requiring the use of highly skilled technicians.

I claim:

1. A process for the manufacture of hydroxylamine sulfonates whichcomprises providing an aqueous solution of ammonium nitrite and asubstance from the group consisting of ammonium bisulte and ammoniumcompounds which react in aqueous solution with sulfur dioxide to formammonium bisulte, dispersing said solution in a stream of sulfurdioxide-containing gas, iiowing said dispersed solution concurrentlywith said stream of gas over a cooled surface providing a large liquidsurface area whereupon reaction liquir flowing concurrently and incontact with said gas stream is obtained, and then separating theresulting reaction liquor from the gas stream.

2. A process as claimed in claim 1, wherein such a proportion ofsolution to gas is maintained that said reaction liquor has a pI-I ofabout 3 to 4.

3. A process as claimed in claim 1, wherein said ammonium compound isammonium hydroxide.

4. A process as claimed in claim i, wherein said ammonium compound isammonium sulite.

5. A process as claimed in claim 1, wherein said gas is roasting gas.

6. A process as claimed in claim l, wherein said dispersing of thesolution is accomplished by spraying the solution into said gas stream.

7. A process as claimed in claim 1, wherein said cooled surface has atemperature between about --10o and +10 C.

8. A process for the manufacture of hydroxyl amine sulfonates whichcomprises providing an aqueous solution of ammonium nitrite and ammoniumhydroxide, spraying said solution into a stream of sulfurdioxide-containing gas, flowing said sprayed solution concurrently withsaid gas stream over a surface which provides a large liquor surfacearea and is sufficiently cold to cool said solution to about 0 C.whereupon reaction liquor flowing concurrently and in contact with saidgas stream is obtained and then separating the resulting hydroxylaminesulfonate-ccntaining liquor from the remaining gas stream.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,010,177 Raschig Nov. 28, 1911 2,458,404 Nagle Jan. 4, 19492,555,667 Zeegers 1 June 5, 1951 OTHER REFERENCES J. W. Mellors ModernInorganic Chem., January 1935, new impression of eighth ed., page 657.Longmans, Green and C0., N. Y.

1. A PROCESS FOR THE MANUFACTURE OF HYDROXYLAMINE SULFONATES WHICHCOMPRISES PROVIDING AN AQUEOUS SOLUTION OF AMMONIUM NITRITE AND ASUBSTANCE FROM THE GROUP CONSISTING OF AMMONIUM BISULFITE AND AMMONIUMCOMPOUNDS WHICH REACT IN AQUEOUS SOLUTION WITH SULFUR DIOXIDE TO FORMAMMONIUM BISULFITE, DISPERSING SAID SOLUTION IN A STREAM OF SULFURDIOXIDE-CONTAINING GAS, FLOWING SAID DISPERSED SOLUTION CONCURRENTLYWITH SAID STREAM OF GAS OVER A COOLED SURFACE PROVIDING A LARGE LIQUIDSURFACE AREA WHEREUPON REACTION LIQUOR FLOWING CONCURRENTLY AND INCONTACT WITH SAID GAS STREAM IS OBTAINED, AND THEN SEPARATING THERESULTING REACTION LIQUOR FROM THE GAS STREAM.